Background：

The protein encoded by this gene is a member of the Ras superfamily of guanosine triphosphate (GTP)-metabolizing enzymes. The encoded protein is expressed in hematopoietic cells， where it functions as a negative regulator of cell growth and survival. This gene may be hypermutated or misexpressed in leukemias and lymphomas. Chromosomal translocations in non-Hodgkin’s lymphoma occur between this locus and B-cell CLL/lymphoma 6 (BCL6) on chromosome 3， leading to the production of fusion transcripts. Alternative splicing in the 5’ untranslated region results in multiple transcript variants that encode the same protein.